Device for stretching leather or the like



Feb.-11, 1969 N. SCI-MD 3,426,558

DEVICE FOR STRETCHING LEATHER OR THE LIKE Filed Aug. 25, 1966 A7270 my United States Patent B 83,424 US. or. 69-46 2 Claims Int. Cl. C14b 1/22, 1/26 ABSTRACT OF THE DISCLOSURE Provided at a station of a hides pass to a power feed is a hide spreading device having means acting substantially midway of the width of a passing hide to guide and hold the latter in a straight direction to the feed, and pairs of power-driven belts on opposite sides of the guide means, of which each pair of belts has adjacent runs extending substantially normal to said direction and gripping a passing hide between them for its widthwise spread.

This invention relates to machines for processing leather or like sheet material in which the material is fed into the machine and is processed by a tool as it moves through the machine. The invention is particularly concerned with-a device provided in the machine for spreading out the material before it reaches the processing tool.

.An example of a machine with which the invention is concerned is a tanning machine in which one end of a hide is introduced into the machine for processing, is withdrawn, turned round and then has its other end introduced into the machine so that the previously unprocessed part is processed.

In conventional tanning machines such as this, most of the processing is carried out in a so-called roller machine. In this, the rollers perform the functions of drying, stretching, fleshing and paring the hide. Paring means the cutting of the leather to uniform thickness which is done for example by pressing the hide against a cylinder knife which consists of a cylinder carrying a helical steel blade which extends from the centre out- Wards in both directions with a constant pitch and the cylinder has at its ends a grinding disc so that a clean cut edge is obtained on the leather.

Most conventional paring machines are arranged so that the leather is processed on entry, that is as the hide is moved into the machine. With machines which operate in this way, any creases in the hide are seen by the operator and they are removed either by hand smoothing as the hide enters the machine or by opening the machine and reinserting the hide. This arrangement has the disadvantage that the output of the machine is rather small because the straightening of the hide hyhand or the opening of the machine and the reinsertion of the hide use up a considerable amount of time. However the spreading and smoothing out of the creases is most important because any creases that remain lower the quality of the hide because the cylinder knife frequently cuts right through the hide at the creases and thus for many purposes the hide is made virtually useless.

A further disadvantage of conventional machines in which the leather is pared as it enters the machine and is spread by hand, is that during spreading the operators hands may get caught between the feed rollers by which the hide is fed into the machine so that his fingers are crushed.

With the aim of overcoming these disadvantages, according to this invention, a machine for processing ice leather or like sheet material in which the material is fed into the machine and is processed by a tool as it moves through the machine, is provided with a device for automatically spreading out the material before it reaches the tool, the device comprising rotating elements arranged on both sides of the centre line of the path of the material and holding members for holding and guiding the centre of the material as it moves between the rotating elements, the elements having their axes of rotation extending substantially parallel to the path of the material and the elements on opposite sides of the centre line being rotated inopposite directions from each other so that as they engage the material they draw it away from the centre line in both directions and spread it laterally.

Preferably the rotating elements consist of either belts or a series of rollers which press against the sheet material and pull it laterally outwards to each side.

Preferably, where belts are provided, these are pressed against the sheet material by guide and pressure bars which act on the side of the belt remote from that which engages the material.

Means are provided for acting on the sheet material to press it against the belts and this means may comprise a second belt on each side of the centre line of the path of the material so that the material is sandwiched between two conveyor belts on each side. Preferably the tension in the belts or the pressure applied by the guide and pressure bars is adjustable.

The belts may be toothed so that they grip the sheet material more efi'iciently.

The holding members are provided because it is important that the centre of the sheet material should be held and guided in its passage through the machine and should not be moved laterally by the belts or other rotat ing elements. The holding members are preferably in the form of a pair of rollers forming a nip between them and having their axes substantially at right angles to the axes of the rotating elements. One of the rollers has its axis fixed in position on one side of the sheet material while the other roller is pressed resiliently towards it with the sheet material trapped in between.

The direction of movement of the surfaces of the belts is perferably not exactly at right angles to the direction of movement of the sheet material through the machine, but is inclined at a small angle so that they apply a component of movement to the sheet material assisting its passage through the machine.

In order to prevent the sheet material which has been spread out from creasing or puckering again before it reaches the processing tool, such as the cylinder knife, guide elements are preferably provided between the holding members and the tool. These guide elements are preferaby in the form of bars arranged to act on opposite faces of the sheet material and displaced so that the path of movement of the sheet material deviates as it passes between them.

When these guide elements are in the form of plates or wide bars, they also serve to protect the rotating elements from shavings of the sheet material which fall down from the cylinder knife during processing. Generally it is sufiicient to provide only one guide element on each face of the sheet material, but there may be more. The elements are preferably arranged so that they can be fitted in without appreciably increasing the distance between the rotary elements and the cylinder knife or other processing tool.

The guide elements may be attached directly to a frame of the machine or they may be attached to the rotary elements which are themselves pivotally attached to the frame of the machine so that the elements acting on one face of the sheet material can be swung out to enable the sheet material to be fed in.

The device may be provided at the inlet to the machine in cases where the sheet material is processed as it is fed in, but preferably it is provided at the outlet so that the machine can be arranged so that the processing is carried out as the sheet material is withdrawn from the machine and not as it is fed in.

An example of a tanning machine constructed in accordance with the invention is illustrated diagrammatically in the accompanying drawings in which:

FIGURE 1 is a side view of the machine with the spreading device as seen in a direction at right angles to the direction of movement of the leather through the machine; and,

FIGURE 2 shows the spreading device alone as seen from below in FIGURE 1 and turned through 90.

The tanning machine comprises a conventional cylinder knife 1, a pressure roller 2 and a holding roller 3. The pressure roller presses the leather 4 against the cylinder knife 1 which rotates in the same direction as the pressure roller so that the part of the cylinder knife adjacent the pressure roller moves contra to the direction in which the leather is fed in and thus effects the paring of the leather.

As shown most clearly in FIGURE 2, two belts 5 are ar-anged on each side of the centre line of the path of travel of the leather through the machine. The leather is sandwiched between two flights of the pair of belts 5 on one side of its centre line and between two flights on the other pair of belts 5 on the other side of its centre line. The belts 5 are supported on rollers 6. As an alternative to the arrangement shown, there may be only two belts 5, one on each side of the centre line of the path of the leather and acting on only one face of the leather. In this case a smooth support surface is provided to act on the opposite face of the leather. Further, instead of the endless belts, a number of rollers lying side by side may be provided in place of each belt.

In the example shown, the leather is guided and held between a pair of holding rollers 7 and *8 mounted between the right hand and left hand pair of belts 5. The roller 7 is fixed in position and the roller 8 is mounted on a U-frame 9 carried by a spring 10 which presses the roller 8 towards the roller 7 and traps the leather resiliently between the two rollers. The pressure between the two rollers 7 and 8 is sufficient to prevent lateral displacement of the leather caused by irregularities in the surface or variations in thickness of the leather as the leather passes through the machine.

The belts 5 pass over guide bars 11 as they engage the leather 4, the guide bars being acted upon by springs 12 to produce the required pressure of the belts 5 against the leather.

As shown in FIGURE 1, guide plates 13 and 14 are provided extending over the whole width, or alternatively over a substantial part of the width of the leather on its passage between the belts 5 and the cylinder knife 1.

The plates 13 and 14 extend laterally away from the faces of the leather 4 sufficiently far to cover the belts 5 so that slithers of leather from the knife 1 are not trapped between the belts and the advancing leather.

As shown in FIGURE 1, the edges of the plates 13 and 14 overlap so that the path of the leather 4 is deviated as it passes between them. This causes the leather to be held in its spread condition brought about by the belts 5. At the left hand side of FIGURE 2, the belts 5 are shown held against both faces of the leather by guide bars 11, but on the right hand side of FIGURE 2 only the top belt 5 is held against the leather by a bar 11 while the bottom belt 5 is not supported and can give to take up irregularities in the surface of the leather.

What is claimed is:

1. A device for spreading flexible hide on its longitudinal pass to a power feed, comprising a pair of cooperating driven feed rollers located at a station of a hides pass to the feed and adapted to engage the opposite surfaces of a passing hide substantially midway of its width to guide and hold it in a straight direction to the feed; and hide spreading units at said station and on opposite sides of said rollers, with each unit comprising a pair of power-driven belts on rotary pulleys, of which the belts have adjacent runs extending substantially normal to said direction and engaging a passing hide on the opposite surfaces thereof for its widthwise draw-out away from said parts, and means yieldingly urging said belt runs against a passing hide.

2. A hide spreading device as in claim 1, in which the axes of the pulleys of each belt are parallel, and the axes of the pulleys of both belts on each side of said parts are inclined to each other to form an acute angle pointing to said feed, so that said adjacent belt runs on each side of said parts define a wedge-like space in which a passing hide is gripped.

References Cited UNITED STATES PATENTS 2,150,264 3/1939 Connor 6946 2,330,271 9/1943 Cutler 6943 2,585,834 2/1952 Pocock 38-143 2,878,602 3/1959 Broad 38143 3,153,291 10/1964 Buss 38143 3,256,624 6/1966 Miller et al 38-143 FOREIGN PATENTS 668,566 3/1952 Great Britain.

PATRICK D. LAWSON, Primary Examiner.

A. R. GUEST, Assistant Examiner. 

